Raman scattering investigations of KY3F10 |
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| Authors: | M. Mortier J. Y. Gesland M. Rousseau M. A. Pimenta L. O. Ladeira J. C. Machado Da Silva G. A. Barbosa |
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| Affiliation: | 1. Equipe de Physique de L'Etat Condensé, URA CNRS No. 807, Université du Maine, 72017 Le Mans Cedex, France;2. Departamento de Fisica ICEx, Universidade Federal de Minas Gerais, C.P. 702, CEP 30161 Belo Horizonte, MG, Brazil |
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| Abstract: | Single crystals of the fluoride compound KY3F10 (Oh5) were studied by Raman scattering from 40 to 950 K. Group theory analysis predicts 3A1g + 4Eg + 6F2g Raman-active modes, but the experimental spectra show two F2g modes missing. Over the whole temperature range the frequency shifts are negligible whereas the line widths show a strong increase with temperature. Both reversible and irreversible line width behaviour are exhibited for different temperature runs, indicating a complex microscopic phenomenon underlying the creation of defects responsible for these line widths and their interaction with the different phonon modes. An approximate activation energy for defect creation of ΔE ≈︁ 0.3 eV can be obtained from the temperature behaviour of the line widths. This activation energy may be connected with the high-temperature ionic conduction mentioned previously for this crystal. |
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